Report of the State Mineralogist . d in order to keepthe temperature of the gases above 600° F. while going through theCottrell dust precipitator which follows. The central column and therabble arms are air-cooled, the resulting hot air being utilized for con-centrate drying and other purposes. A Brown recording pyrometer SANTA CLARA COUNTY. 219 is connected in at the furnace exit to enable regulation of the fumetemperature. This furnace is stated not to work economically on material coarserthan J inch. Up to 58 tons have been treated in 24 hours; but it seemsto do its best work at between 40
Report of the State Mineralogist . d in order to keepthe temperature of the gases above 600° F. while going through theCottrell dust precipitator which follows. The central column and therabble arms are air-cooled, the resulting hot air being utilized for con-centrate drying and other purposes. A Brown recording pyrometer SANTA CLARA COUNTY. 219 is connected in at the furnace exit to enable regulation of the fumetemperature. This furnace is stated not to work economically on material coarserthan J inch. Up to 58 tons have been treated in 24 hours; but it seemsto do its best work at between 40 and 50 tons. Feeding and discharg-ing are both automatic. The feed hopper is shown in Photo No. 22,while the housing for the discharge may be seen in the lower left-handcorner of Photo No. 23. A steel ore-car is kept under the dischargechute, and when filled is trammed out by hand to the dump. By reason of the dust raised and thrown into the fume circulation asthe ore is mechanically scraped from one hearth to the next, a bother-. Photo No. 22. Top, or Drying-hearth, of Herreschoff Furnace. Feed hopper is seen inupper part. Photo by W. W. Bradley. some accumulation of dust was at first obtained in the condensers. Tocorrect this and keep the dust from passing into the condensers, a Cot-trell fume precipitator, called the hot treater was installed betweenthe furnace and the first condenser. (See Photo No. 20.) To preventthe mercury from condensing in this treater, the temperature of thegases (as already mentioned) is kept above 600° F. on leaving thefurnace. As a precaution to recover any quicksilver which might havecondensed in case of irregularities occurring in the furnace operation,the hot-treater dust is run into a settling tank before being dischargedto the dump. Following the last condensing chamber is a second Cot-irell precipitator (Photo No. 23), called the cold treater, to throwdown any remaining mercury mist in the fumes. It is stated that alittle quicksilver is obt
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectminesandmineralresou
